Automated guided vehicles (AGVs) are battery-powered, cell-driven vehicles used to transport materials and other items from one location to another without any accompanying operator. AGVs are being increasingly used in the material handling industry and are an important part of the shift in production planning from high speed production to focus instead on efficient transportation of materials between work stations as well as into and out of storage. AGVs are important in this regard since they are capable of responding readily to frequently changing transport patterns and can be integrated into modern manufacturing plants, where flexible material handling systems are now required to perform an efficient routing of materials.
This flexibility of AGVs also manifests itself in the numerous different types of vehicles available as well as multiple guide paths for the vehicles. In addition, the number of vehicles in use can be easily changed, as pick up and drop off points and travel paths of the AGVs therebetween can be determined by software programming. Changes in the guide paths of vehicles can be made when the system is not operating; thus, there is no loss of efficiency. In addition, the control program for the AGVs can be altered without interfering with their operations.
Further, AGVs provide high reliability. In this regard, if an AGV breaks down, a spare vehicle can be used as a replacement, which is not the case in most other material handling systems. For example, if a conveyor breaks down, the result may be that the entire manufacturing facility becomes inoperable.
Moreover, the operating costs of AGVs are often lower than other types of material handling systems, since AGVs are unmanned and otherwise not as labor intensive as other systems. Further, the initial investment costs of AGVs are often less than other material handling systems.
In addition, AGVs are typically easily interfaced with other systems, including conveyors and overhead transport systems. AGVs are now widely used in material handling systems, textile manufacturing systems, container handling applications, and vehicle handling applications in numerous fields, including in the aerospace, automotive, clean room, food and beverage, mail processing, manufacturing, newsprint, pharmaceutical, plastics, and warehouse fields.
The design of the travel paths or routes of the AGVs has a significant impact on the overall system performance and reliability, since this directly affects the travel time and complexity of the software used to control the scheduling and travel paths of the AGVs. The present disclosure seeks to address improvements in the routing of AGVs.
AGVs are constrained by software to follow virtual guide paths from one location to another. Generally, there are sections of the guide path intended for general AGV travel as well as sections of the guide path or lanes specifically dedicated for the storage of inventory products, etc. The exact route than an AGV travels is typically controlled by control software that oversees all of the AGVs in a particular system and prevents them from colliding with each other. Usually, there are one or, at most, a few alternative routes to get to one location or another. If there is more than one route, the control software typically chooses the shortest route, which is thought to be the most efficient.
However, current routing of AGVs does not consider obstructions in the path of the AGV which may include inventory or product, a stalled AGV, a pathway that is too narrow for the AGV or its load to pass through, etc. Current routing of AGVs also does not factor in whether an AGV can route underneath a storage location, such as underneath shelving or a rack structure on which inventory or items to be retrieved are stored. In addition, current AGVs' routing control does not bear in mind the number of turns of the AGV that must be used to complete the path. Each turn that an AGV makes requires that it decelerate, rotate its wheels, and accelerate, thus causing a reduction of average speed of the vehicle at each turn, in addition to causing wear and tear on the vehicle tires as well as the underlying floor. In multi-floor travel paths, current routing of AGVs ignores the effect of routing an AGV through several elevators to reach a desired floor rather than using one or a fewer number of elevators. The system, method, and software of the present disclosure seek to address the foregoing shortcomings of current AGV control systems, methods, and software in seeking to achieve the most expeditious routing of AGVs.